Sodium Propionate — Frequently Asked Questions

Where the calcium would interfere, or where solubility matters. In chemically leavened products calcium disrupts the leavening reaction and reduces volume. In liquid dosing, spray application onto grain or incorporation into an aqueous formulation, the calcium salt's limited solubility is a handling problem. The sodium salt resolves both.

Appreciably more than the calcium salt, which is what makes it suitable for solution dosing and spray application. That allows a concentrated dosing solution to be made up, reducing storage volume and giving more accurate metering than dispersing a sparingly soluble powder would permit.

Where sodium loading is controlled, yes. In a feed ration or a formulation with a sodium specification, the contribution from the preservative should be included in the calculation. For most industrial mould control applications the quantity is small enough not to matter, but it should be checked rather than assumed.

There is no sharp cut-off, but activity declines as pH rises because less of the propionate exists as the undissociated acid that crosses the cell membrane. Propionates remain useful at the near-neutral pH of bread crumb, around 5.5 to 6, where benzoate and sorbate are largely inactive, which is precisely why they dominate in bakery.